FAQ

Heat rate is one measure of the efficiency of electrical generators/power plants that convert a fuel into heat and into electricity. The heat rate is the amount of energy used by an electrical generator/power plant to generate one kilowatthour (kWh) of electricity. The U.S. Energy Information Administration (EIA) expresses heat rates in British thermal units (Btu) per net kWh generated. Net generation is the amount of electricity a power plant supplies to the power transmission line connected to the power plant. Net generation accounts for all the electricity that the power plant consumes to operate the plant’s generator(s) and other equipment, such as fuel feeding systems, boiler water pumps, cooling equipment, and pollution control devices.

To express the efficiency of a generator or power plant as a percentage, divide the equivalent Btu content of a kWh of electricity (3,412 Btu) by the heat rate. For example, if the heat rate is 10,500 Btu, the efficiency is 33%. If the heat rate is 7,500 Btu, the efficiency is 45%.

The average amounts of coal, natural gas, and petroleum liquid fuels used to generate a kilowatthour (kWh) of electricity is approximately:

• Coal–1.13 pounds/kWh
• Petroleum liquids–0.08 gallons/kWh
• Natural gas–7.43 cubic feet/kWh